WhatsApp is really popular here in Switzerland. But what these guys are doing is not only embarrassing, it's becoming suicide.
http://www.h-online.com/security/news/item/WhatsApp-threatens-legal-action-against-API-developers-1716912.html
The preceding article in German is even more concrete on the matter: apparently, it's not possible to cancel your account with WhatsApp (users report that the function to close the account in the app seems to do nothing), but once you have an account everyone that has your phone number and IMEI or MAC (depending on Android or iPhone) can send messages pretending to be you, even after you've uninstalled the app!
http://www.h-online.com/security/news/item/WhatsApp-threatens-legal-action-against-API-developers-1716912.html
The preceding article in German is even more concrete on the matter: apparently, it's not possible to cancel your account with WhatsApp (users report that the function to close the account in the app seems to do nothing), but once you have an account everyone that has your phone number and IMEI or MAC (depending on Android or iPhone) can send messages pretending to be you, even after you've uninstalled the app!






